In a typical recorder, paper is moved with constant velocity in one direction so as to represent an independent variable such as time, and a stylus is moved across the paper in an orthorgonal direction in accordance with the amplitude of a signal representing a dependent variable. Certain signals, such as those appearing at the output of the detector of a chromatograph, exhibit changes in amplitude that are rapid at some times and slow at others. Recording such signals with fidelity requires that the stylus be able to move with sufficient speed to follow the most rapid changes in amplitude. Furthermore, if annotation or other messages are to be recorded along with the signal, the stylus must be able to move faster than required by the signal in order to have some free time in which to perform this function. A mechanism for driving the stylus with sufficient speed to record the signal faithfully and at the same time permit the writing of annotations is expensive.